Ceratonia siliqua is a flowering evergreen tree from the Fabaceae or pea family. It is also known as St John’s-bread and Carob Tree. This tree is widely cultivated in different parts of the world for its edible fruits or legumes. Their attractive appearance has some ornamental value as well.

Carob Tree Scientific Name

The scientific name for these plants is Ceratonia siliqua.

Ceratonia siliqua (Carob Tree) Description

They have an attractive appearance with dense dark green foliage.

Picture 1 – Carob Tree

Height: They grow up to 10 meters (33 feet) in height.

Trunk: The trunk of an 18 year old tree grows around 85 cm in diameter. It is covered with rough, brown bark. Stout branches grow from the trunk.

Crown: The broad and thick foliage is semi spherical in shape.

Leaves: Their dark green, leathery leaves grow between 10 and 30 cm (3.9 and 7.9 inches) in length. The alternate, pinnate leaves have 6 to 10 opposite leaflets (sometimes 12) that are rounded at the apex. Each leaflet is oval in shape, growing 2 to 8 cm long and 1 to 5 cm broad. The leaves generally do not have terminal leaflets.

Flowers: They have small red flowers that are borne in clusters. The trees are generally dioecious in nature which means male and female flowers grow on separate trees. Small flowers are arranged in a spiral manner along the axis of the inflorescence. They blossom during autumn in September and October.

Fruit: The Carob Trees bear oblong, brown fruits that grow from 10 to 30 cm in length and 1.5 to 3.5 cm in width. The fruits are straight or a little curvy with thickened margin. These fruits become tough, fibrous and shiny when they ripen late in summer. They have 5 to 15 hard seeds situated in the pale brown, soft and glutinous pulp. When the fruits are completely dry, the seeds become loose and rattle inside the pod.

Ceratonia siliqua (Carob Tree) Distribution

It is native to the Middle East and Mediterranean regions. Their distribution range include the southern regions of Portugal, southern Spain, Catalonia, Valencia, Malta, Sicily, Sardinia, southern parts of Greece and Greek islands like Crete and Samos.

Ceratonia siliqua (Carob Tree) Growing Condition

Here are the conditions required for the proper growth of the Carob Tree:

Picture 2 - Carob Tree Flower

Soil: Well drained loamy soil is ideal for them. They are very salt-tolerant and can adapt to various types of soils. But they cannot survive in waterlogged conditions.

Soil pH Requirements: The pH level of the soil need to be between 6 and 8.6 for their proper growth.

Sunlight: They prefer full sunlight.

Water Requirements: These trees can survive dry conditions with the annual average rainfall ranging from 250 mm to 500 mm. They can even tolerate draughts, but they need at least 500 mm rainfall in a year to bear good quality fruit.

Temperature: They can tolerate extreme hot temperature up to 50°C. Matured trees are frost tolerant and can survive temperatures down to -7°C. But Carob shoots and flowers cannot endure temperatures below -4 °C.

Climate: Warm temperate as well as subtropical climates are ideal for them.

How to Grow Ceratonia siliqua (Carob Tree)

Countries like Spain, Italy, Portugal and Morocco are among the top Carob Producers. This tree is generally grown from seeds, requiring little maintenance. It is generally wind pollinated, but sometimes insects may also help in the pollination.

Picture 3 – Carob Tree Seed

Ceratonia siliqua (Carob Tree) Seed Sowing

The seed pods need to be opened gently to extract the seeds.

Dried seeds should be soaked in warm water (80 °F) for at least 4 hours until the seeds are swollen.

These swollen seeds should be planted in wet sandy loam soil.

Spring is the ideal season for sowing the seeds.

They should be sown at a depth of 1 to 2 inches.

The soil should be kept very moist for the first six weeks after seed sowing.

Ceratonia siliqua (Carob Tree) Seed Germination

Carob seeds germinate quite easily.

They sometimes require to be treated with hot water or acid for breaking their hard seed coat.

Ceratonia siliqua (Carob Tree) Transplanting

The seedlings can be transferred outdoors once they grow 2 to 3 inches in height.

They should be planted 1 to 2 inches deep in well drained moist soil.

One should plant them in a sandy location with full sunlight.

The soil temperature should be above 64°F and the pH level of the soil should range between 6.2 and 8.6.

Ceratonia siliqua (Carob Tree) Watering

Seedlings and young trees require regular watering. The matured Carob trees do not need watering as natural rainfall provides them with adequate amounts of water. They can also grow in extreme dry climates. But one should water them in case rainfall is scarce, otherwise they cannot bear good fruit. Care should be taken not to overwater them.

Ceratonia siliqua (Carob Tree) Fertilization

Any special fertilization is not necessary for them. These trees are able of adapting to various types of poor soil. Nitrogen fertilizers can be applied to the Carob trees as nitrogen is believed to be beneficial for their fruit production. Applying phosphorus or potassium based fertilizers along with nitrogen is advisable, especially after the harvesting season.

Ceratonia siliqua (Carob Tree) Pests and Diseases

They are usually not affected by any pests and diseases. In Spain, the polyphagous larva attacks their trunk and brunches. These larvas mostly affect young trees of this species.

Picture 4 – Ceratonia Siliqua Seedpods

Insects known as carob midge attack the young pods of the Ceratonia siliqua trees mainly in Cyprus. Other pests known to attack them include carob midge, black aphids and odium ceratoniae. Small rodents like gophers and rats occasionally damage their roots and bark. One should use proper pesticides to fight any pest related disease. It is also advisable to consult local expert to learn the proper way of fighting such conditions.

Ceratonia siliqua (Carob Tree) Harvesting

Harvesting is done during late summer or early winter, depending on the region. The fruits are harvested after they ripen and turn dark brown. The Carob fruits can be harvested by knocking them down using long poles. Fiber nets are laid out directly under the tree for collecting the knocked down pods. One should take care not to ruin the flowers while harvesting the fruits with a pole.

Ceratonia siliqua (Carob Tree) Uses and Benefits

The sweet and fibrous fruit pulp is eaten both raw and dried.

It is used as a substitute for chocolate in cakes and drinks.

The pulp is highly beneficial for human health as it is rich in various proteins.

Protein rich flour is made from the seeds of their fruits. The flour is widely used for baking.

This flour is also used in cosmetics.

These seeds are used for making a gum which is used as a substitute for gum tragacanth.

This gum is sometimes used as a stabilizer, thickening agent and a substitute for eggs.

The pulp of the Carob fruits has astringent properties.

The fruits, seeds and bark of Carob are used for curing diarrhea and cough.

They are also used in the treatment of Irritable Bowel Syndrome.

The Carob trees are often grown in parks and roadsides in many US states like Arizona and California.

Tannin is obtained from their bark.

The hard wood of these trees is used for making walking sticks.

Their fruits are widely used as animal fodder in many countries.

Ceratonia siliqua (Carob Tree) Interesting Facts

Here are some interesting facts about this tree:

Carob seeds are sometimes known as Karat. The name is derived from the unit of measurement “carat” because all the seeds are of a uniform size and shape.

The high tannin content of the Carob fruits can cause some adverse effects when consumed in large amounts.